Shutter arrangement for windowed door of heat cleaning oven

ABSTRACT

The titled apparatus in which a movable shutter arrangement is disposed in the door and connected to the latching means for the door for movement to a closed position when the latching means is operated to a position to initiate a heat cleaning operation of the oven, and is moved to an open position when the latching means is operated back to a position permitting the door to be opened.

United States Patent 1 Barnett et al.

SHUTTER ARRANGEMENT FOR WINDOWED DOOR OF HEAT CLEANING OVEN Inventors: Eugene J. Barnett, Wesley E.

Shreffler, both of Mansfield, Ohio Westinghouse Electric Corporation, Pittsburgh, Pa.

Filed: Oct. 25, 1968 Appl. No.: 770,488

Assignee:

US. Cl ..126/l97, 126/200 Int. Cl ..F23m 7/00 Field of Search ..126/197, 200

References Cited UNITED STATES PATENTS 3/1967 Baughman et a1 ..126/200 Primary ExaminerCarro1l B. Dority, Jr. Att0rneyF. H. Henson and E. C. Arenz [57] ABSTRACT The titled apparatus in which a movable shutter arrangement is disposed in the door and connected to the latching means for the door for movement to a closed position when the latching means is operated to a position to initiate a heat cleaning operation of the oven, and is moved to an open position when the latching means is operated back to a position permitting the door to be opened.

16 Claims, 11 Drawing Figures PATENTEUHAR 1 31m 3.720.196

SHEET 20F 6 F I I l l I l l I ll 8 PATENIEDMAR 1 3mm SHEET 3 BF 6 FIG.5.

PATENTEUHAR 1 sum SHEET 5 OF 6 FIG.8.

O I 0 J SHUTTER ARRANGEMENT FOR WINDOWED DOOR OF HEAT CLEANING OVEN BACKGROUND OF THE INVENTION 1. Field of The Invention This invention pertains to the art of windowed doors for cooking ovens, and particularly to that aspect of it dealing with heat cleaning oven doors having windows therein and shutter arrangements for the windows.

2. Description of The Prior Art The best prior art known to us in this particular field is found in U.S. Pat. Nos. 3,311,106 and 3,362,369. In both of these arrangements as disclosed, a shutter is manually operated to a closed position independently of the operation of the latching means for the doors, and interlock means are provided to insure that a heat cleaning cycle may not be initiated until the interlock means is disabled by the movement of the shutter arrangernent to a closed position, Additionally, in at least the earlier of these patents, the structural arrangement includes air flow passages through certain parts of the door which do not lend themselves readily to receiving what we would consider an adequate amount of thermal insulation.

Our invention provides an arrangement which we consider improved in at least some respects and which readily lends itself to use in an oven door having an already established general design.

SUMMARY OF THE INVENTION In accordance with our invention, the arrangement includes a forwardly-open oven provided with a door having at least a pair of windows spaced apart therein, latching means operable between one and. an opposite position for effecting latching and unlatching, respectively, of the door to the oven, a shutter assembly in the door operable between open and closed positions in the generally planar space between the windows in the door, and means connecting the shutter assembly to the latching means for operating the shutter assembly between the closed and open position in accordance with operation of the latching means between the one and the opposite positions thereof.

In the best mode of the invention currently contemplated, the shutter assembly includes a pair of opposite shutters located beyond opposite edges of the opening, and linkage means connecting the shutters for movement in generally parallelogram fashion between the closed and open positions. It is also considered desirable with the particular oven construction and latching means construction associated therewith that the connecting means between the latching means and the shutter assembly include a lost motion connection for permitting limited movement of the latching means in the closed position of the shutter assembly without operating the shutter assembly from a closed position. Other features and modifications will be taken up hereinafter.

DRAWING DESCRIPTION FIG. 1 is a perspective view of a cooking range provided with an oven construction embodying our invention;

FIG. 2 is a fragmentary vertical sectional view corresponding to one taken through the center of the door and with the shutters open;

FIG. 3 is a partly-broken elevational view of the outer face of the door illustrating the general relationship of the shutter assembly to other parts of the door and to the latching means;

FIG. 4 is a face view of the shutter assembly and connected latching assembly apart from the door to better illustrate the relationship of these parts when the shutter assembly is in an open position;

FIG. 5 is a view similar to FIG. 4, but illustrating the shutter assembly and latching assembly in a position corresponding to the shutters being closed and the door being latched;

FIG. 6 is a partly-broken isometric view of the latching assembly and part of the connecting linkage, the parts being shown in a position corresponding to the door being unlatched and the shutters open;

FIG. 7 is a view similar to FIG. 6, but illustrating the latching mechanism parts in a position resulting when it is attempted to unlatch the door and open the shutters before the heat cleaning cycle has ended;

FIG. 8 is a partly diagrammatic face view of an alternate embodiment of the invention;

FIG. 9 is a horizontal section taken along the line lX--IX of FIG. 8;

FIG. 10 is a fragmentary face view of another shutter arrangement according to the invention; and

FIG. 11 is a fragmentary vertical sectional view of the structure of FIG. 9.

PREFERRED EMBODIMENTS The invention is illustrated as embodied in the free standing cooking range of FIG. 1 which includes a for wardly-open oven 10 defined by the oven liner and cabinet structure 12, containing both a lower heating element 14, and an upper element (not shown), and a door 16 for closing the oven.

The upper center portion of the door 16 (FIGS. 1 and 2) carries a manually-operated latching handle 18 for operating latching mechanism 20 to a position securing the door when a heat cleaning cycle is to be initiated, and for placing lock effecting means in a condition to effect locking of the door through an electrical or other system (not shown) after the oven temperature has risen above the range of normal cooking tern peratures. One example of an arrangement for accomplishing this with latching means carried by the door is disclosed in Nagel U.S. Pat. No. 3,390,909, to which reference should be had for details. In accordance therewith, a latching bolt 22 (best seen in FIGS. 6 and 7 is turned up out of the slot 23 in the top edge of the door when the handle 18-is pivoted from a horizontal (unlatched) to a vertically depending (latched) position, with the door in a closed position. As the bolt turns up out of the slot it engages keeper structure and a bell crank assembly 24 (FIG. I.) illustrated in block form as mounted in the oven framing structure which overlies the top center edge of the door when the door is closed. Through a linkage connecting the bell crank to lock-effecting-means at the rear of the oven, the lock-effecting-means is placed in condition permitting the initiation of a heat cleaning cycle which complies with the requirements for safety, all of which is disclosed in detail in the noted Nagel patent.

The door 16 (FIG. 2) includes an outer panel 26, an inner panel 28, and a muffle panel 30 which are secured together to form a generally hollow door structure. The structure includes in part the general structural arrangement of Tilus US. Pat. application Ser. No. 581,582 relating to the manner in which the various panels are secured together and the way in which the muffle panel secures the gasket disposed between the rim of the muffle panel and the inner panel.

Each of the panels includes a cut-out rectangular portion, aligned with each other in the assembly of the panels, which receives the transparent window panes. The outer panel receives a window assembly 32 (FIG. 2) comprising two spaced-apart panesof glass 34 and 36 held in a perimetric frame 38. The inner window assembly 40 comprises a single pane of glass 42 secured at its margin to the muffle panel, which is in turn secured to the inner panel. An intermediate, shallow, pan-shaped panel 44 having a central cut-out portion has its lower edge flange 46 secured to the inner panel 28, and its upper edge pressed against the inner panel along a line near the upper margin of the door. This intermediate panel serves, with the facing portions of the inner panel, and with the glass panes 36 and 42, to define a generally planar space 48 which extends both above and below the windows a distance equal to about half the height of the windows, and over half of the distance toward the edge of the door from the side edges of the windows. This space 48 accommodates the shutter portions of the shutter assembly in their movement between open and closed positions. Thermal insulation 49 may be provided in most of the hollow spaces in the door except for the space in which the shutters move, the space occupied by the latch assembly, and that space registering with the viewing windows.

The shutter assembly (FIGS. 2-5) includes an upper shutter 50 and a lower shutter 52. In their currently preferred form, they are generally flat, sheet-form elements with thickened and oppositely beveled marginal edges 54 and 56 facing each other. With these edges meeting each other when the shutters are closed, the complementing bevels provide an overlap. The shutters are linked to each other for relative movement toward and away from each other with a parallelogram type linkage. This linkage includes arms 58 and 60 pivotally secured at their centers to the bights of U-shaped brackets 62 attached to the outwardly-facing face of the inner panel 28 at opposite sides along the border of the cut-out in the inner panel. The ends of the arms are pivotally attached to the shutters at the locations shown (which gives a relationship between the shutters in their movement corresponding to that of a parallel rule) so that as both arms are rotated in a counterclockwise direction from their FIGS. 3 and 4 position (i.e., open position) toward a FIG. position (i.e., closed position) the shutters will be moved in translational fashion toward each other and will meet and close to each other with the ends of the shutters being in alignment. When the arms are moved in a clockwise direction, the shutters are moved back to the FIGS. 3 and 4 open position from the FIG. 5 position.

It is .noted that the holes 63 (FIG. 4) in the brackets 62 are elongated in a direction toward the side edges of the oven door to provide compensation for differential expansion and contraction of the shutters and connecting arms during the high temperature periods encountered in the cleaning cycle.

The connecting means between the shutter assembly and the latching assembly in the illustrated embodiment includes a link 64 (FIGS. 2, 4, 5) pivotally secured at one end to the oven-facing face of the thickened margin 54 of the top shutter 50, the other. end being pivotally secured to the outer end of a main tongue portion 66 of a lever. The part of the lever which extends up into the latch assembly bracket is bent over upon itself to form a U-shaped portion 68 (FIGS. 6 and 7) provided with aligned openings therein to freely receive the shaft 70 which carries the latch handle 18. Another tongue portion 72 of the lever extends away from U-shaped portion 68 at about a right angle from the main tongue portion, and has a laterally projecting tab 74 which is received in a notch 76 formed in an edge of the latch member 78. The latch member 78 includes a hub 80 which is pinned to the shaft 70, the bolt portion 22, and a pawl 82 which extends at about a right angle from the bolt. The latch bracket, which journals the shaft 70 and generally contains the latching parts, also supports a leaf-spring mounted roller 84 disposed for engagement with the outer ends of the bolt 22, the tongue 72 and the pawl 82.

The manner in which the latching means and connecting means work is as follows. With oven door unlatched, the roller 84 is engaged as shown in FIGS. 4 and 6 against the end edge surface of the bolt 22 to prevent the latch member 78 from rotating, from the weight of the handle, in a clockwise direction. Since the tap 74 against one edge of notch 76 prevents the tongue 66 and link 64 from moving the shutters are held open. In latching the door, as the latching handle is turned clockwise, the latch member 78 secured to shaft 70 rotates corresponding to carry the end edge of the bolt 22 past the roller 84. The rotation of the latch member is transmitted to the lever through the tab and notch connection so that as the lever rotates clockwise, its tongue 66 forces the link 64 in a direction which moves the shutters in a closing direction. When the bolt 22 has reached its extreme end position (FIG. 5) in which the door is latched, the outer ends of both tongue 72 and pawl 82 have been pulled past the roller 84, which urges them in an upwardly direction. This force is transmitted to the shutters and accordingly tends to hold them together.

It is the nature of the latching and locking arrangement as disclosed in the noted Nagel patent that tolerance and clearance requirements of the bolt and keeper structure dictate that there be some play in the latch mechanism when it is latched. That is, the latch handle may be rotated in the order of 20-25 toward an unlatched position when the door is latched. This does not result in unlatching of the door, of course, since the locking arrangement prevents that. However, to insure that the shutters remain closed if the latch handle is turned toward an unlatched position during a cleaning operation, a lost-motion connection between the tab and notch is provided by making the notch 76 sufficiently wider than the tab 74 that the 2025 movement of the latch handle toward an unlatched position can occur without the lever being required to follow. Thus, while the latching handle can be turned counterclockwise to carry the pawl 82 just past the roller 84 as shown in FIG. 7, the tongue 72 remains in its engaged position where the roller holds it up. Hence the shutters will stay in a fully closed position until a reduced oven temperature releases the locking means and permits the latch to be fully unlatched.

While the invention has been described principally in connection with a pair of shutters arranged for movement in a parallelogram or parallel rule fashion, it is contemplated that in accordance with our invention other alternative modes for carrying out the invention may be provided. Thus, in FIGS. 8 and 9 an arrangement is illustrated in which a pair of oppositelydisposed half shutters are mounted to be moved directly toward each other from positions above and below the window through a cable and pulley arrangement.

The parts in FIGS. 8 and 9, which correspond to those in the previous figures are identically enumerated. While only the arrangement at the right-hand end of the shutters is illustrated, it will be understood that the arrangement at the left-hand end is the same, but inverted. At both ends of the shutters, a pair of rotatable pulleys 86 and 88 are mounted on an upright bracket 94 that is mounted to the inner panel 28 and aligned parallel to the door edges. A separate cable section 90 extends around each pulley. Both ends of each shutter includes means 91 and 92 to which the ends of the shutter are connected. The ends 1 16 and 1 17 of the cable sections 90, are fastened to the ends of the extensions 91 and 92. The extension 92 for the lower shutter is slidably connected to the bracket 94 by means of two slots 96 which cooperate with the pins 98 fastened to extension 92 to guide the shutters in their movement. The member 91 is a bar that is rigidly connected to the upper shutter and connects the ends 116 of the cable sections 90. The connection between the shutters and the latching means 20 is generally the same as that described in connection with FIGS. 1 through 6. When the upper shutter 50 is forced downwardly toward a closed position, the bar 91 moves down with the upper shutter while the extension 92 moves up with the lower shutter 52 by virtue of the cable arrangement and connections.

Finally, in one other embodiment as illustrated in FIGS. and 11, the shutter assembly takes the form of a series of vertically-disposed, relatively narrow slats which are arranged in the same fashion as vertical Venetian blinds and are ganged for operation to a closed position in accordance with movement of the latching means to a latched position. As illustrated, the individual slats 102 are mounted in a box 104 in which they are secured at top and bottom for pivotal movement about a vertical axis. A gang bar 106 is connected to an offset crank part 108 connected to each of the slats so that when the gang bar is moved laterally, each of the slats is rotated. A tension spring 110 is connected to a lug 112 connected to the gang bar and serves to normally urge the slats to an open position. A lever 1 14 which moves with the latching handle shaft in the same fashion as described in connection with the embodiment of FIGS. 1-6, is rotated down into contact with the lug 112 and overcomes the force of the spring 110, and moves the gang bar to effect closure of the shutter assembly by rotating the slats when the latching handle is turned to a latched position. When the latching handle is turned back to an unlatched position after the end of a cleaning cycle, the release of the lug 112 by the rotation of the lever 114 away from the lug results in the tension spring returning the slats to an open position as shown in FIG. 10.

It is noted that the preferred embodiment is that of the pair of shutters arranged to move in parallel rule fashion. The Venetian blind arrangement is considered inferior to the preferred arrangement in that it requires that the viewer to look substantially directly through the slats and parallel with their planes to get the best view of the interior of the oven. It will be apparent that a view into the oven at an angle relative to the plane of the slats in their open position results in considerable obstruction of the view. The parallel rule fashion of movement is also preferred over the cable and pulley arrangement since problems with alignment in keeping the opposite shutters parallel in their movement arise more readily with the cable and pulley arrangement. While these may be overcome, it is considered that the additional complexity and cost of the parts for solving such alignment problems are probably not merited.

We claim as our invention:

1. An oven construction for a heat cleaning oven including:

means defining a forwardlyopen overt,

a door for closing said oven;

latching means for said door and operable between one and an opposite position for effecting latching and unlatching, respectively, of said door to said oven defining means;

at least a pair of windows spaced apart in said door on opposite sides of a generally planar space defined in part between said windows;

a shutter assembly in said door operable between open and closed positions in said generally planar space; and

means connecting said shutter assembly to said latching means for operating said shutter assembly between a closed and an open position in accordance with operation of said latching means between said one and said opposite positions respectively.

2. An oven construction according to claim 1 wherein:

said connecting means includes a lost motion connection therein for permitting limited movement of said latching means in said one position without operating said shutter assembly from a closed position.

3. An oven construction according to claim 1 wherein:

said shutter assembly includes a pair of shutters in a plane parallel to the plane of said door, and linkage means connecting said shutters for movement in generally parallelogram fiashion between said closed and open positions.

4. An oven construction according to claim 3 wherein:

said shutter assembly includes a pair of links connected to said pair of shutters to correspond in form to the form of a parallel rule, and means pivotally attaching the central portion of each of said links to said door on opposite sides of said windows so that when said shutters are moved from an open position to a closed position, the

ends of said shutters move from an offset relationship to a generally aligned relationship. 5. An oven construction according to claim 4 wherein:

said attaching means includes slots extending in a direction parallel to the length of said shutters to compensate for differential expansion and contraction of said shutter assembly relative to said door. 6. An oven construction according to claim 1 wherein:

said door is of generally hollow construction includ- I ing an inner panel and a spaced-apart outer panel, and a generally pan-shaped, intermediate panel having a central cut-out portion registering with said windows, the portions of said intermediate panel above and below said windows separating said generally planar space from the space in said door between said intermediate panel and said outer panel; and thermal insulation in said latter space.

7. In a range oven door adapted to close an access opening to an oven chamber and having a window opening closed by a window,

a shutter assembly associated with said window comprising a plurality of movable louver members arranged across the area of said window to cover and uncover said window,

means operably joining to move said members in unison including yieldable means for holding said members in position to uncover said window to provide viewing areas therethrough, and

said yieldable means being extended externally of said door to be operationally engaged to position said members to cover said window against the force of said yielding means.

8. A cooking range having an oven chamber and an access opening to said chamber, a door for closing said opening, latching means for said door, said door having a window comprising a pair of transparent panels arranged in spaced apart relation for viewing therethrough said oven chamber, a shutter arrangement for said window comprising,

a plurality of movable segments between said transparent panels and being arranged to cooperatively form an intermediate planar wall between said panels in one position and assume independent transverse positions in another, and

said latching means being operable with said movable segments to actuate said segments into at least one of said positions.

9. A range oven door provided with a transparent window formed of a plurality of transparent panels in spaced apart relation, shutter means for selectively covering and uncovering said window, the combination comprising,

a frame member interposed in fixed relation between certain of said transparent panels to extend along certain marginal edge portions of said transparent panels, 7

a plurality of louvers reciprocally mounted to said frame member and adapted to alternately cover and uncover said window,

means operably connecting said louvers and being operable to reciprocally move said louvers in unison,and

latching means for said door being adapted to engage, and operate said means to set said louvers in position to cover said window while effecting a latching of said door.

10. A range oven door of claim 9 including,

means associated with said louvers to return said louvers to position to uncover said window,

said lastmentioned means being made operative by said latching means in effecting the unlatching of said door.

1 1. A range oven door of claim 9 including,

resilient means associated with said operable means to yieldably hold said louvers in position uncovering said window.

12. A range oven door of claim 11 including,

said latching means being operable to disengage from said operable means upon unlatching said door,

said resilient means being operable by said means in the latching of said door to store energy for sub sequent use to operate said means upon its release from said latching means to reposition said louvers to uncover said window.

13. A door for closing an access opening to an oven chamber formed in a range body, latching means for selectively latching said door including a latch member on said range body being operable to engage a keeper carried by said door, a window opening in said door covered by a window assembly including transparent glass panes arranged in vertically spaced apart relation for viewing therethrough said oven chamber, a shutter assembly interposed between certain of said glass panes and extending substantially across the viewing area of said window assembly and comprising;

a frame member,

a plurality of louvers each being journaled to said frame member for reciprocal movement,

means interconnecting said louvers to pivotally actuate said louvers in unison into a first position and a second position wherein said first position positions said louvers to provide unobstructed viewing areas between said louvers for see through into said chamber through said window and in the second position said louvers cooperatively forming a planar wall between said glass panes covering the viewing area of said window, and

said means being operably engaged by said latch member to be actuated to actuate said louvers to said second position as said latch member is being operated to engage said keeper.

14. The door of claim 13 including;

said louvers having the characteristic of being a heat reflective barrier when in the second position.

15. In a range having a door for closing an access opening of an oven chamber formed in the range body, latching means for said door including a latch member on said range body being operable to alternately engage and disengage with a keeper carried on said door, a window opening in said door covered by a window assembly including transparent glass panes arranged in vertically spaced relation supported in a frame, shutter means for said window and being operable to selectively cover and uncover said window comprising,

a frame member affixed between certain of said glass panes and being extended along marginal edges thereof,

latch member, and

means arranged with and being operable by said drive means to store energy to operably actuate said drive means in setting said louvers in uncover position upon said drive means being released by said latch member.

16. In a range of claim 15 including;

said last mentioned means being a resilient member to yieldably hold said louvers in uncover position. 

1. An oven construction for a heat cleaning oven including: means defining a forwardly-open oven, a door for closing said oven; latching means for said door and operable between one and an opposite position for effecting latching and unlatching, respectively, of said door to said oven defining means; at least a pair of windows spaced apart in said door on opposite sides of a generally planar space defined in part between said windows; a shutter assembly in said door operable between open and closed positions in said generally planar space; and means connecting said shutter assembly to said latching means for operating said shutter assembly between a closed and an open position in accordance with operation of said latching means between said one and said opposite positions respectively.
 1. An oven construction for a heat cleaning oven including: means defining a forwardly-open oven, a door for closing said oven; latching means for said door and operable between one and an opposite position for effecting latching and unlatching, respectively, of said door to said oven defining means; at least a pair of windows spaced apart in said door on opposite sides of a generally planar space defined in part between said windows; a shutter assembly in said door operable between open and closed positions in said generally planar space; and means connecting said shutter assembly to said latching means for operating said shutter assembly between a closed and an open position in accordance with operation of said latching means between said one and said opposite positions respectively.
 2. An oven construction according to claim 1 wherein: said connecting means includes a lost motion connection therein for permitting limited movement of said latching means in said one position without operating said shutter assembly from a closed position.
 3. An oven construction according to claim 1 wherein: said shutter assembly includes a pair of shutters In a plane parallel to the plane of said door, and linkage means connecting said shutters for movement in generally parallelogram fashion between said closed and open positions.
 4. An oven construction according to claim 3 wherein: said shutter assembly includes a pair of links connected to said pair of shutters to correspond in form to the form of a parallel rule, and means pivotally attaching the central portion of each of said links to said door on opposite sides of said windows so that when said shutters are moved from an open position to a closed position, the ends of said shutters move from an offset relationship to a generally aligned relationship.
 5. An oven construction according to claim 4 wherein: said attaching means includes slots extending in a direction parallel to the length of said shutters to compensate for differential expansion and contraction of said shutter assembly relative to said door.
 6. An oven construction according to claim 1 wherein: said door is of generally hollow construction including an inner panel and a spaced-apart outer panel, and a generally pan-shaped, intermediate panel having a central cut-out portion registering with said windows, the portions of said intermediate panel above and below said windows separating said generally planar space from the space in said door between said intermediate panel and said outer panel; and thermal insulation in said latter space.
 7. In a range oven door adapted to close an access opening to an oven chamber and having a window opening closed by a window, a shutter assembly associated with said window comprising a plurality of movable louver members arranged across the area of said window to cover and uncover said window, means operably joining to move said members in unison including yieldable means for holding said members in position to uncover said window to provide viewing areas therethrough, and said yieldable means being extended externally of said door to be operationally engaged to position said members to cover said window against the force of said yielding means.
 8. A cooking range having an oven chamber and an access opening to said chamber, a door for closing said opening, latching means for said door, said door having a window comprising a pair of transparent panels arranged in spaced apart relation for viewing therethrough said oven chamber, a shutter arrangement for said window comprising, a plurality of movable segments between said transparent panels and being arranged to cooperatively form an intermediate planar wall between said panels in one position and assume independent transverse positions in another, and said latching means being operable with said movable segments to actuate said segments into at least one of said positions.
 9. A range oven door provided with a transparent window formed of a plurality of transparent panels in spaced apart relation, shutter means for selectively covering and uncovering said window, the combination comprising, a frame member interposed in fixed relation between certain of said transparent panels to extend along certain marginal edge portions of said transparent panels, a plurality of louvers reciprocally mounted to said frame member and adapted to alternately cover and uncover said window, means operably connecting said louvers and being operable to reciprocally move said louvers in unison, and latching means for said door being adapted to engage, and operate said means to set said louvers in position to cover said window while effecting a latching of said door.
 10. A range oven door of claim 9 including, means associated with said louvers to return said louvers to position to uncover said window, said last mentioned means being made operative by said latching means in effecting the unlatching of said door.
 11. A range oven door of claim 9 including, resilient means associated with said operable means to yieldably hold said louvers in position uncoVering said window.
 12. A range oven door of claim 11 including, said latching means being operable to disengage from said operable means upon unlatching said door, said resilient means being operable by said means in the latching of said door to store energy for subsequent use to operate said means upon its release from said latching means to reposition said louvers to uncover said window.
 13. A door for closing an access opening to an oven chamber formed in a range body, latching means for selectively latching said door including a latch member on said range body being operable to engage a keeper carried by said door, a window opening in said door covered by a window assembly including transparent glass panes arranged in vertically spaced apart relation for viewing therethrough said oven chamber, a shutter assembly interposed between certain of said glass panes and extending substantially across the viewing area of said window assembly and comprising; a frame member, a plurality of louvers each being journaled to said frame member for reciprocal movement, means interconnecting said louvers to pivotally actuate said louvers in unison into a first position and a second position wherein said first position positions said louvers to provide unobstructed viewing areas between said louvers for see through into said chamber through said window and in the second position said louvers cooperatively forming a planar wall between said glass panes covering the viewing area of said window, and said means being operably engaged by said latch member to be actuated to actuate said louvers to said second position as said latch member is being operated to engage said keeper.
 14. The door of claim 13 including; said louvers having the characteristic of being a heat reflective barrier when in the second position.
 15. In a range having a door for closing an access opening of an oven chamber formed in the range body, latching means for said door including a latch member on said range body being operable to alternately engage and disengage with a keeper carried on said door, a window opening in said door covered by a window assembly including transparent glass panes arranged in vertically spaced relation supported in a frame, shutter means for said window and being operable to selectively cover and uncover said window comprising, a frame member affixed between certain of said glass panes and being extended along marginal edges thereof, a plurality of louvers journaled to said frame member for reciprocal movement and being arranged when set in cover position to form a planar wall between and extending substantially across the viewing area of certain of said glass panes, means movably interconnecting said louvers for movement in unison, drive means adapted to be operably engaged and released alternately by said latch member, said drive means coupled to move and hold said louvers in cover position while in engagement with said latch member, and means arranged with and being operable by said drive means to store energy to operably actuate said drive means in setting said louvers in uncover position upon said drive means being released by said latch member. 